As an apparatus for producing a single crystal, there is an apparatus in which a seed crystal is dipped in a raw material solution in a crucible disposed inside a chamber and pulled up.
Patent Document 1 discloses an apparatus for producing a Si (silicon) single crystal by the Czochralski method, where a heating means is disposed on the outer circumference of a crucible, a thermal insulator is disposed on the outer circumference thereof, and a cooling jacket is disposed on the further outer circumference thereof. In the cooling jacket, a gas for cooling is flowed.
In the production apparatus disclosed in Patent Document 1, a seed crystal dipped in a Si solution in the crucible is pulled up to produce a Si single crystal. An observation window for confirming the state of the Si single crystal during pulling up or the Si solution in the crucible is disposed on the top surface of the cooling jacket housing.